open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello,

two questions concerning bed load transport with Sisyphe v6p3r2:

(1) How is the situation detected and treated, in which we have the bottom surface movement -against- the direction of the flow and the sediment discharge (e.g. a sand bank growing against the flow direction, before an island or an non-erodible obstacle, channel bifurcation, etc.)? Especially in the case, when there is enough sediment so that the bottom gets higher than the water surface and we have a shoreline moving against the general transport and flow direction? [Bed celerity opposite to the direction of flow and sediment transport.]

(2) Is there any simple test case available showing the ability or disability of the present Exner equation slolver implemented in Sisyphe ("positive depths"?) to model such typical situation -- just to play with?

Best regards,
jaj

Dear Jaj,
(1) You mean, a situation similar to the propagation of antidunes?
(2) Nope, but that could be a nice test case. Thanks for the idea.

Cheers,

Pablo

Hello Pablo,

well, I am not sure if the situation in the model I refer to is an antidune as wikipedia describes it: Wikipedia-Antidune, but the setting is similar. For an antidune, you need a supercritical flow; a dune grows against the current and it grows also in the amplitude -- well, until a breakup or, maybe drying out occurs. Very strongly interacting with the current, so something the classical Exner equation is not supposed to describe... Anyway, also by subcritical flow -- deposition (by bed load) of material against the direction of the current and transport.

I would be very thankful for a clear statement if this kind of situation can be modelled with Sisyphe.

Best regards,
jaj